Just want to ask if anyone has experienced this kind of problem on their tableau dashboards that sometimes suddenly you will get an error message of Data Source Error "Unable to connect to the data source" when dashboard was loading. Then after you click Try Again or click refresh the dashboard will just load normally.

Details of my project for your reference Dashboard project was deployed separately to the data sources and data sources was also deployed on its own in tableau server.

Meaning that the Dashboard was connected in the data sources in tableau server in Live Extract.

I hope you can help me figure out how to eliminate this kind of errors.

With data connection errors, it may be fastest to file a support ticket. There are many things at play - (usually networking or incorrect drivers) that can be at fault. Please open a ticket at https://support.tableau.com if you have not been able to resolve this error.